Submarine-cable construction



Dec. 3, 1929. A. M. CURTIS I SUBMARINE CABLE CONSTRUCTION Filed NOV. l0,1923 Patented Dec. 3, i929 UNETE!) STATES PATENT Orrick".

COMPANY, NCORFORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK,

SUBMARINE-CABLE CONSTRUCTION Application led November 10, 1923. `SerialNo.`673,972.

This invent-ion relates to iii'ipioveinents in suluiiariue cableconz-rt'ruction.

Submarine cables as commonly constructed for deep sea signal liliescomprise a centra-lv 'conductor Wliiclimay consist of one or moreindividual conducting Wires or strands, a

thick-insulating envelope of gutta percha or otherinsulatingniaterialgand a protecting armor consisting of a sheath ofsteel Wires Wound spil-ally about the interior portion of the cable.This armor serves as a protection i' against mechanical injuryand togive the cable the necessary tensile strength.

-Theweiglit which must be supported. in lowering a cable at a sea depthof tivo or three' n iiles is very to las much as Jfour tons. It vhasbeen Idisto tliistensile. force, tends to straighten'out.

Atleast two, disadvantageouseffects ensue froin this actiony ofv thearmor.

. istlie-tendencyof the armor Wires to un-v lieve this by greatertwisting at a point onv twist in thatl portion of tliecable where theItensile forceis greatest and Where least-op?- position to Vsuchuntwisting isjmet and to re` or approaching the sea. ,floorwith theresult that a bend,link, 'or other y*deformation oc-fcurs at that'-point. stricting etl'ect 'on V'The 'second is the oontl'ieinterior'gof thec'able las the armor Wirestend to straighten out underthe influence ofthe greattensileforce 'f to which they I`aresiibj'ected.g Bends' andY kinks make -it diiiicult to' again'lift thecable vwithout damaging itfand.` are, accordingly,

very harmful.. Even if the cable is not to fbe 'raised they are apt toiinpose'such strains on the .dielectricmaterial .as to speedily inducefaults. i

'There has recently 'been developed a'sub-` marine cable continuouslyloaded with a tape ot' aliiagnetic 'alloy able magnetic properties atthe low flux densities encounteredin vsubmarine telegraph cable practiceas to-increase by several timestliefeasible signalling speedswhich canvbe attained with exstin'gjcables. lThe inagnetic properties of thisalloy are highlyv dependent upon conditions of-stiainto which it may beminimum. guarding suoli a cable against nonuniforin great and thetensileforce exerted on the cable. at the ship inay amount The novelconnection' with subject. 'Attention-is called to the discussion of thismaterial in an article by Arnold and lillmenpubli'slied in the Journalof the Franknostri-fia' ivi. Gomis, or EAST ORANGE, NEW JERSEY, AssrGNoR'ro WESTERN ELECTRIC' lin Institute, May, 1923, vol. .195, No. 5. i

-Forloaded cable lof this type it is particularly Viiuliiortan'tthatdistortions, deformations, and nonuuiform stress be reduced to a Theimperative necessity of pressures, or kinking will therefore be apparent. v

AAn objectief -tliisinvention is to prevent or re'duce the nonu'iiiformstresses and del formations towhichdeep sea cables are subliected.

furtlier' object of the'invention is to maintain tlie'niagneticqualities of a loaded cableas nearly as possible unimpaired by coveredthat the spiral armor, when sub]ect which tof'a large degree causestliedistorting`.forces tobe neutralized.

This neutralization is attaincdb o .i Desing Y l e to the. .twistingforceof thejspiral armor, anl

equal and opposite twisting force ofA a sec- 4ond armor having a.lspiral inftlieoppositc di- The invention, itself, however, both. as tothe details of itsorganiz'ation audits mode 4of operation Will'best beunderstood by reference -to the following description ,taken -in theaccompanying drawing' in wli'ich Fig.` illustrates rinsectionja-"cablestructure..embodying the invention and"l 5`.ig. $1

features, which are ,considered characteristic ofthe invention, are"pointed .out with pa-rticularity intheappended claims.

Q'llustrates in elevation a* 'portion ofthev cable y structure with'parts broken away. which. has such v'reinark- Referring tothe drawing,1' represents. the l central copper conductor surrounded byaplurality-'of-helically'applied-segmental conductf ing'strips'wliichcocperate with member-1v flexible conductorof sutlicie'nt conf.

to form' a ducting cross section. -Surrouiidiiig tlieflexis the loadingmaterial 3 which i ing 5 of gutta percha.A

tape wound about the stranded conductor. This tape preferably consistsof a composition known as permalloy and which includes about 80% ofnickel and 20% of iron. The characteristics of this material aredisclosed in; theFranklin Institute article to which reference has beenpreviously made.

Surroundingr the loaded conductor is a thin layer of a semi-fluidcompound 4 which also fillsv all the interstices of the conductor. Itspurpose is to provide a uniform distribution of pressure about theperinalloy tape whenl i i the c able is subjected to pressure as in immerslon in great depths A of water. Outside the layer of compound is theinsulating cover- About the gutta percha insulating covering f is aserving 6 of jute which providesa 'founvso dation for the innerarmorwires 7 which are wound 4in a right hand spiral or clockwise advancingrtoward the right. Outside this armor is another sei-vino' 8 of jute. Asecond armorv similar tol the first but wound in a left hand spiralconsists of wires 9 preferably so designed in size and numberas toneutralize the twisting tendencyof'the inner armor.

As it is desirable to be able to use standard round wires for the armor,the outer wires 9 may be` of a smaller sizethan wires 7. How# ever, theouter armor may be put on with a different pitch `or lay than-the innerarmorA i and may 1n some instances consist of larger wires. Y

The essential requirement', however, is that .the twisting or deformingaction of the one armor, when the cable is subjected to tension,

p cramping. A serving l1 of jute surrounds sand, moreover, valong thevremainder 0f the cable which vthe Vpositely wound armor,

penetrate.

be neutralized to the greatest possible degree by the opposing forceofthe other armor.

. It will be appreciated as' disclosed, maybe readily coiled in anydirection. To facilitate coiling each armor wireis preferably providedwith a. wrapping of jute or similar material to space adjacent armorwires and to enable them' to approach each other without the outerarmor.

Should unequal static pressures occur which are temporary or notexcessively 4different in magnitude, the semi-fluid compound willliowuntil these are equalized. If, however,rthe

cable were to kink the armor wires might be" forced toward the centralconductor wlth suchpressure as to establish an area of solid contactsinto which the compound could not The forces at .different points ofsuch areas might be altogethernonuniform greatly in excess of theforcescompound readily equalizes. The occurrence fof such excessive pressuresAis minimized by this invention' and the differences in pressure can bereadily equalized by the semiuid comat various points are maintainedless than pound. There is accordingly a peculiar coteri al whereby thata cable with opto .facilitate coiling, toprevent kinking and otherdeformation, and to make easier laying and subsequent raising of thecable.

Vhat is claimed is:

A deep sea cable comprising an vinsulated conductor and two oppositelywound spiral armors surrounding said insulated conductor each of `saidJarmors comprising individual wires separated from each-other and fromthe wires of the other 'armor by yielding mathe armored. cable may bereadily coiled in any direction. In witness whereof, I hereuntosubscribe my name this 3rd day of November A.-.D.,

`AUST-EN M. CURTIS.

fluid in preventing permanent in-

